The present disclosure herein relates to an optical coupler, and more particularly, to an optical coupler including a plurality of waveguides.
As the semiconductor industry has advanced to a high level, highly integrated and high-speed semiconductor integrated circuits are demanded. However, due to various reasons, it has become difficult more and more to meet the requirements for semiconductor integrated circuits. For example, data communication through existing electric lines causes phenomena, such as skin effects and crosstalk as the size of a device is decreased. Therefore, high-speed data communication has had a limitation.
Optical coupling and optical communication using an optical device enable ultrahigh-speed data communication without such side effects. Especially, silicon-based optical devices have merits of being producible by using an existing CMOS process. Thus, optical communication using silicon-based optical devices has been spotlighted as a field which can replace the data communication using electric lines. Since the sizes of silicon-based optical devices are small, it is possible to integrate individual optical devices on a single chip. In addition, it is possible to monolithically integrate electronic devices and optical devices on a substrate.
In general, silicon-based optical devices have sizes smaller than core diameters of optical fibers. Thus, an optical coupler is required to optically couple silicon-based optical devices and optical fibers. Many researches for minimizing optical loss and enabling packaging costs to be reduced in coupling optical fibers and optical devices are being actively carried out.